IV size was zero on CBC and CTR modes,
causing a bug triggered by skcipher.

Fixing this  adding a correct size.
Signed-off-by: Leonidas Da Silva Barbosa <leosilva@linux.vnet.ibm.com>
Signed-off-by: Paulo Smorigo <pfsmorigo@linux.vnet.ibm.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>